The schedule for the metabolic testing will include: Day 0 baseline overnight chamber with no stimulation. Days 1-4 Resting metabolic rate (RMR) will be performed hourly with variable LHS DBS settings. The settings will be changed approximately every 15 minutes after the DBS settings are changed. Day 4 overnight chamber at ideal metabolic rate setting. After RMR test on Day 4, the subject will have a dual-energy x-ray absorptiometry (DXA) scan performed to assess body composition.